Reiner was born in Namibia, attended the local Deutsche Schule Otjiwarongo and then Michaelhouse, where he obtained the best matric results in Natal. He then studied at Stellenbosch University where he completed three degrees cum laude and received the faculty medal. He also sang in the University Choir. He was subsequently awarded a scholarship to Cambridge to study International Relations. There he sang in the Trinity College Choir and established himself as a counter-tenor soloist. He finally left his academic pursuits behind to study singing at the Mozarteum in Salzburg and the Schola Cantorum Basiliensis in Basel, Switzerland. It was here that he started to retrain the baritone range of his voice.
As a soloist he has worked with numerous formations. Recitals of song and melodrama remain a particular priority. In 2003 he joined the vocal ensemble Singer Pur, Germany’s leading vocal ensemble that has performed in over 40 countries and in recent years has won the ECHO Klassik prize three times, considered Europe’s most prestigious CD award.